In the 1980's network communication evolved from local networking on site (the Ethernet Local Area Network or LAN) to Inter-networking between sites. As the usage of Internet as a service network grew so did its commercial orientation. And by the late 1980s the commercial Internet Service Providers (ISPs) started to make their debut. Today, computers (for single users or part of a corporate environment) are serviced by more than 30,000 ISPs across the world, predominantly operating on a commercial basis as a service provider. The services range from the mass-marketing of simple access products to service-intensive operations that provide specialized service levels to more localized internet markets. We are mainly concerned with ISPs providing networks, referred to more generally as network service providers.
With networks playing an ever-increasing role in today's electronic economy, network service providers need to manage their networks more effectively. The five major functional areas of “network management” and the current tools and techniques that exist to handle them are: fault management, configuration management, security management, performance management, and accounting management.
With the rapid growth of network usage, network service providers are currently facing ever increasing expectations from their customers to the quality of service (minimum delay, maximum reliability, high bandwidth for data transfer rates, low costs, etc). The main task is to satisfy the quality of service parameters while minimizing the usage of network resources such as capacity of the network lines. But there are other issues relating to future sales, strategic planning and business development. One concerns Service Level Agreements (SLAs) with their customers.
An SLA is a service contract between a network service provider and a subscriber, guaranteeing a particular service's quality characteristics. SLAs usually focus on network availability and data-delivery reliability. Violations of an SLA by a service provider may result in a prorated service rate for the next billing period for the subscriber.
Thus it is important for a network service provider to know whether it can issue an Service Level Agreement (SLA) to another customer without violating any existing SLAs. Here it needs to estimate what is the largest new workload that the network can handle with respect to network availability and data-delivery reliability.
In strategic planning, the objective is to investigate how to revise the existing network topology (and connection points to external nodes) such that the resource utilization is minimized and more balanced. The problem is to minimize the resource utilization by determining which backbone lines are overloaded, and to add lines to the network to redistribute the load. For a given workload, the question is where to add the lines in the network and what is the required bandwidth of each backbone line such that the capacity of the new network topology is greater, i.e. can deal with a larger load. Another question concerns which node should be used to connect a new customer to the network. This should be the one which minimises resource utilisation and expands capacity in the most cost effective way.
Another key issue which needs to be addressed by the service provider is whether the current business of an ISP can be extended, in terms of number of customers and connections to other ISPs.
For business development, one key question is how to maximise the number of customers. This clearly depends on the existing workload and where it is distributed. Another related question is how other service providers should be connected to the backbone. This should be done so as to minimise resource utilisation.
Each of the issues discussed above represents an optimisation problem. Current network management packages provide essentially device-oriented information whereas the issues can only be resolved on the basis of service-oriented information. Device oriented information tells us about the state of a network and its data flows at a given time. This is the core information provided by network management protocols such as the Simple Network Management Protocol (SNMP), which is used in most network management systems. But this does not address the optimisation problems mentioned above.
U.S. Pat. No. 6,061,331 relates to a method of estimating source-destination traffic in a packet-switching network utilising a decomposition method. The method uses measurements made over multiple disjoint time periods of traffic coming into the network at each node and measurements of traffic on each link. The method subsequently uses these measurements to set up linear programming problems for finding an approximate source-destination traffic matrix that optimally fits the measured data.